#include"mrrr.h"
static int c__1 = 1;
static int c__2 = 2;

int pdlarre(char *range, int *n, double *vl, double *vu, int *il, int *iu,
		double *d__, double *e, double *e2, double *rtol1, double *rtol2,
		double * spltol, int *nsplit, int *isplit, int *m, double *w,
		double *werr, double *wgap, int *iblock, int *indexw, double *gers,
		double *pivmin, double *work, int * iwork, int *info) {
	/* System generated locals */
	int i__1, i__2;
	double d__1, d__2, d__3;


	/* Local variables */
	int i__, j;
	double s1, s2;
	int mb;
	double gl;
	int in, mm;
	double gu;
	int cnt;
	double eps, tau, tmp, rtl;
	int cnt1, cnt2;
	double tmp1, eabs;
	int iend, jblk;
	double eold;
	int indl;
	double dmax__, emax;
	int wend, idum, indu;
	double rtol;
	int iseed[4];
	double avgap, sigma;
	int iinfo;
	bool norep;

	int ibegin;
	bool forceb;
	int irange;
	double sgndef;

	int wbegin;

	double safmin, spdiam;

	bool usedqd;
	double clwdth, isleft;
	double isrght, bsrtol, dpivot;

	/*  -- LAPACK auxiliary routine (version 3.2) -- */
	/*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
	/*     November 2006 */

	/*     .. Scalar Arguments .. */
	/*     .. */
	/*     .. Array Arguments .. */
	/*     .. */

	/*  Purpose */
	/*  ======= */

	/*  To find the desired eigenvalues of a given real symmetric */
	/*  tridiagonal matrix T, DLARRE sets any "small" off-diagonal */
	/*  elements to zero, and for each unreduced block T_i, it finds */
	/*  (a) a suitable shift at one end of the block's spectrum, */
	/*  (b) the base representation, T_i - sigma_i I = L_i D_i L_i^T, and */
	/*  (c) eigenvalues of each L_i D_i L_i^T. */
	/*  The representations and eigenvalues found are then used by */
	/*  DSTEMR to compute the eigenvectors of T. */
	/*  The accuracy varies depending on whether bisection is used to */
	/*  find a few eigenvalues or the dqds algorithm (subroutine DLASQ2) to */
	/*  conpute all and then discard any unwanted one. */
	/*  As an added benefit, DLARRE also outputs the n */
	/*  Gerschgorin intervals for the matrices L_i D_i L_i^T. */

	/*  Arguments */
	/*  ========= */

	/*  RANGE   (input) CHARACTER */
	/*          = 'A': ("All")   all eigenvalues will be found. */
	/*          = 'V': ("Value") all eigenvalues in the half-open interval */
	/*                           (VL, VU] will be found. */
	/*          = 'I': ("Index") the IL-th through IU-th eigenvalues (of the */
	/*                           entire matrix) will be found. */

	/*  N       (input) int */
	/*          The order of the matrix. N > 0. */

	/*  VL      (input/output) DOUBLE PRECISION */
	/*  VU      (input/output) DOUBLE PRECISION */
	/*          If RANGE='V', the lower and upper bounds for the eigenvalues. */
	/*          Eigenvalues less than or equal to VL, or greater than VU, */
	/*          will not be returned.  VL < VU. */
	/*          If RANGE='I' or ='A', DLARRE computes bounds on the desired */
	/*          part of the spectrum. */

	/*  IL      (input) int */
	/*  IU      (input) int */
	/*          If RANGE='I', the indices (in ascending order) of the */
	/*          smallest and largest eigenvalues to be returned. */
	/*          1 <= IL <= IU <= N. */

	/*  D       (input/output) DOUBLE PRECISION array, dimension (N) */
	/*          On entry, the N diagonal elements of the tridiagonal */
	/*          matrix T. */
	/*          On exit, the N diagonal elements of the diagonal */
	/*          matrices D_i. */

	/*  E       (input/output) DOUBLE PRECISION array, dimension (N) */
	/*          On entry, the first (N-1) entries contain the subdiagonal */
	/*          elements of the tridiagonal matrix T; E(N) need not be set. */
	/*          On exit, E contains the subdiagonal elements of the unit */
	/*          bidiagonal matrices L_i. The entries E( ISPLIT( I ) ), */
	/*          1 <= I <= NSPLIT, contain the base points sigma_i on output. */

	/*  E2      (input/output) DOUBLE PRECISION array, dimension (N) */
	/*          On entry, the first (N-1) entries contain the SQUARES of the */
	/*          subdiagonal elements of the tridiagonal matrix T; */
	/*          E2(N) need not be set. */
	/*          On exit, the entries E2( ISPLIT( I ) ), */
	/*          1 <= I <= NSPLIT, have been set to zero */

	/*  RTOL1   (input) DOUBLE PRECISION */
	/*  RTOL2   (input) DOUBLE PRECISION */
	/*           Parameters for bisection. */
	/*           An interval [LEFT,RIGHT] has converged if */
	/*           RIGHT-LEFT.LT.MAX( RTOL1*GAP, RTOL2*MAX(|LEFT|,|RIGHT|) ) */

	/*  SPLTOL (input) DOUBLE PRECISION */
	/*          The threshold for splitting. */

	/*  NSPLIT  (output) int */
	/*          The number of blocks T splits into. 1 <= NSPLIT <= N. */

	/*  ISPLIT  (output) int array, dimension (N) */
	/*          The splitting points, at which T breaks up into blocks. */
	/*          The first block consists of rows/columns 1 to ISPLIT(1), */
	/*          the second of rows/columns ISPLIT(1)+1 through ISPLIT(2), */
	/*          etc., and the NSPLIT-th consists of rows/columns */
	/*          ISPLIT(NSPLIT-1)+1 through ISPLIT(NSPLIT)=N. */

	/*  M       (output) int */
	/*          The total number of eigenvalues (of all L_i D_i L_i^T) */
	/*          found. */

	/*  W       (output) DOUBLE PRECISION array, dimension (N) */
	/*          The first M elements contain the eigenvalues. The */
	/*          eigenvalues of each of the blocks, L_i D_i L_i^T, are */
	/*          sorted in ascending order ( DLARRE may use the */
	/*          remaining N-M elements as workspace). */

	/*  WERR    (output) DOUBLE PRECISION array, dimension (N) */
	/*          The error bound on the corresponding eigenvalue in W. */

	/*  WGAP    (output) DOUBLE PRECISION array, dimension (N) */
	/*          The separation from the right neighbor eigenvalue in W. */
	/*          The gap is only with respect to the eigenvalues of the same block */
	/*          as each block has its own representation tree. */
	/*          Exception: at the right end of a block we store the left gap */

	/*  IBLOCK  (output) int array, dimension (N) */
	/*          The indices of the blocks (submatrices) associated with the */
	/*          corresponding eigenvalues in W; IBLOCK(i)=1 if eigenvalue */
	/*          W(i) belongs to the first block from the top, =2 if W(i) */
	/*          belongs to the second block, etc. */

	/*  INDEXW  (output) int array, dimension (N) */
	/*          The indices of the eigenvalues within each block (submatrix); */
	/*          for example, INDEXW(i)= 10 and IBLOCK(i)=2 imply that the */
	/*          i-th eigenvalue W(i) is the 10-th eigenvalue in block 2 */

	/*  GERS    (output) DOUBLE PRECISION array, dimension (2*N) */
	/*          The N Gerschgorin intervals (the i-th Gerschgorin interval */
	/*          is (GERS(2*i-1), GERS(2*i)). */

	/*  PIVMIN  (output) DOUBLE PRECISION */
	/*          The minimum pivot in the Sturm sequence for T. */

	/*  WORK    (workspace) DOUBLE PRECISION array, dimension (6*N) */
	/*          Workspace. */

	/*  IWORK   (workspace) int array, dimension (5*N) */
	/*          Workspace. */

	/*  INFO    (output) int */
	/*          = 0:  successful exit */
	/*          > 0:  A problem occured in DLARRE. */
	/*          < 0:  One of the called subroutines signaled an internal problem. */
	/*                Needs inspection of the corresponding parameter IINFO */
	/*                for further information. */

	/*          =-1:  Problem in DLARRD. */
	/*          = 2:  No base representation could be found in MAXTRY iterations. */
	/*                Increasing MAXTRY and recompilation might be a remedy. */
	/*          =-3:  Problem in DLARRB when computing the refined root */
	/*                representation for DLASQ2. */
	/*          =-4:  Problem in DLARRB when preforming bisection on the */
	/*                desired part of the spectrum. */
	/*          =-5:  Problem in DLASQ2. */
	/*          =-6:  Problem in DLASQ2. */

	/*  Further Details */
	/*  The base representations are required to suffer very little */
	/*  element growth and consequently define all their eigenvalues to */
	/*  high relative accuracy. */
	/*  =============== */

	/*  Based on contributions by */
	/*     Beresford Parlett, University of California, Berkeley, USA */
	/*     Jim Demmel, University of California, Berkeley, USA */
	/*     Inderjit Dhillon, University of Texas, Austin, USA */
	/*     Osni Marques, LBNL/NERSC, USA */
	/*     Christof Voemel, University of California, Berkeley, USA */

	/*  ===================================================================== */

	/*     .. Parameters .. */
	/*     .. */
	/*     .. Local Scalars .. */
	/*     .. */
	/*     .. Local Arrays .. */
	/*     .. */
	/*     .. External Functions .. */
	/*     .. */
	/*     .. External Subroutines .. */
	/*     .. */
	/*     .. Intrinsic Functions .. */
	/*     .. */
	/*     .. Executable Statements .. */

	/* Parameter adjustments */
	--iwork;
	--work;
	--gers;
	--indexw;
	--iblock;
	--wgap;
	--werr;
	--w;
	--isplit;
	--e2;
	--e;
	--d__;

	/* Function Body */
	*info = 0;

	/*     Decode RANGE */

	if (plsame(range, "A")) {
		irange = 1;
	} else if (plsame(range, "V")) {
		irange = 3;
	} else if (plsame(range, "I")) {
		irange = 2;
	}
	*m = 0;
	/*     Get machine constants */
	safmin = dlamch("S");
	eps = dlamch("P");
	/*     Set parameters */
	rtl = sqrt(eps);
	bsrtol = sqrt(eps);
	/*     Treat case of 1x1 matrix for quick return */
	if (*n == 1) {
		if (irange == 1 || irange == 3 && d__[1] > *vl && d__[1] <= *vu
				|| irange == 2 && *il == 1 && *iu == 1) {
			*m = 1;
			w[1] = d__[1];
			/*           The computation error of the eigenvalue is zero */
			werr[1] = 0.;
			wgap[1] = 0.;
			iblock[1] = 1;
			indexw[1] = 1;
			gers[1] = d__[1];
			gers[2] = d__[1];
		}
		/*        store the shift for the initial RRR, which is zero in this case */
		e[1] = 0.;
		return 0;
	}
	/*     General case: tridiagonal matrix of order > 1 */

	/*     Init WERR, WGAP. Compute Gerschgorin intervals and spectral diameter. */
	/*     Compute maximum off-diagonal entry and pivmin. */
	gl = d__[1];
	gu = d__[1];
	eold = 0.;
	emax = 0.;
	e[*n] = 0.;
	i__1 = *n;
	for (i__ = 1; i__ <= i__1; ++i__) {
		werr[i__] = 0.;
		wgap[i__] = 0.;
		eabs = (d__1 = e[i__], fabs(d__1));
		if (eabs >= emax) {
			emax = eabs;
		}
		tmp1 = eabs + eold;
		gers[(i__ << 1) - 1] = d__[i__] - tmp1;
		/* Computing MIN */
		d__1 = gl, d__2 = gers[(i__ << 1) - 1];
		gl = min(d__1, d__2);
		gers[i__ * 2] = d__[i__] + tmp1;
		/* Computing MAX */
		d__1 = gu, d__2 = gers[i__ * 2];
		gu = max(d__1, d__2);
		eold = eabs;
		/* L5: */
	}
	/*     The minimum pivot allowed in the Sturm sequence for T */
	/* Computing MAX */
	/* Computing 2nd power */
	d__3 = emax;
	d__1 = 1., d__2 = d__3 * d__3;
	*pivmin = safmin * max(d__1, d__2);
	/*     Compute spectral diameter. The Gerschgorin bounds give an */
	/*     estimate that is wrong by at most a factor of SQRT(2) */
	spdiam = gu - gl;
	/*     Compute splitting points */
	pdlarra(n, &d__[1], &e[1], &e2[1], spltol, &spdiam, nsplit, &isplit[1],
			&iinfo);
	/*     Can force use of bisection instead of faster DQDS. */
	/*     Option left in the code for future multisection work. */
	forceb = false
	;
	/*     Initialize USEDQD, DQDS should be used for ALLRNG unless someone */
	/*     explicitly wants bisection. */
	usedqd = irange == 1 && !forceb;
	if (irange == 1 && !forceb) {
		/*        Set interval [VL,VU] that contains all eigenvalues */
		*vl = gl;
		*vu = gu;
	} else {
		/*        We call DLARRD to find crude approximations to the eigenvalues */
		/*        in the desired range. In case IRANGE = INDRNG, we also obtain the */
		/*        interval (VL,VU] that contains all the wanted eigenvalues. */
		/*        An interval [LEFT,RIGHT] has converged if */
		/*        RIGHT-LEFT.LT.RTOL*MAX(ABS(LEFT),ABS(RIGHT)) */
		/*        DLARRD needs a WORK of size 4*N, IWORK of size 3*N */
		pdlarrd(range, "B", n, vl, vu, il, iu, &gers[1], &bsrtol, &d__[1],
				&e[1], &e2[1], pivmin, nsplit, &isplit[1], &mm, &w[1], &werr[1],
				vl, vu, &iblock[1], &indexw[1], &work[1], &iwork[1], &iinfo);
		if (iinfo != 0) {
			*info = -1;
			return 0;
		}
		/*        Make sure that the entries M+1 to N in W, WERR, IBLOCK, INDEXW are 0 */
		i__1 = *n;
		for (i__ = mm + 1; i__ <= i__1; ++i__) {
			w[i__] = 0.;
			werr[i__] = 0.;
			iblock[i__] = 0;
			indexw[i__] = 0;
			/* L14: */
		}
	}
	/* ** */
	/*     Loop over unreduced blocks */
	ibegin = 1;
	wbegin = 1;
	i__1 = *nsplit;
	for (jblk = 1; jblk <= i__1; ++jblk) {
		iend = isplit[jblk];
		in = iend - ibegin + 1;
		/*        1 X 1 block */
		if (in == 1) {
			if (irange == 1
					|| irange == 3 && d__[ibegin] > *vl && d__[ibegin] <= *vu
					|| irange == 2 && iblock[wbegin] == jblk) {
				++(*m);
				w[*m] = d__[ibegin];
				werr[*m] = 0.;
				/*              The gap for a single block doesn't matter for the later */
				/*              algorithm and is assigned an arbitrary large value */
				wgap[*m] = 0.;
				iblock[*m] = jblk;
				indexw[*m] = 1;
				++wbegin;
			}
			/*           E( IEND ) holds the shift for the initial RRR */
			e[iend] = 0.;
			ibegin = iend + 1;
			goto L170;
		}

		/*        Blocks of size larger than 1x1 */

		/*        E( IEND ) will hold the shift for the initial RRR, for now set it =0 */
		e[iend] = 0.;

		/*        Find local outer bounds GL,GU for the block */
		gl = d__[ibegin];
		gu = d__[ibegin];
		i__2 = iend;
		for (i__ = ibegin; i__ <= i__2; ++i__) {
			/* Computing MIN */
			d__1 = gers[(i__ << 1) - 1];
			gl = min(d__1, gl);
			/* Computing MAX */
			d__1 = gers[i__ * 2];
			gu = max(d__1, gu);
			/* L15: */
		}
		spdiam = gu - gl;
		if (!(irange == 1 && !forceb)) {
			/*           Count the number of eigenvalues in the current block. */
			mb = 0;
			i__2 = mm;
			for (i__ = wbegin; i__ <= i__2; ++i__) {
				if (iblock[i__] == jblk) {
					++mb;
				} else {
					goto L21;
				}
				/* L20: */
			}
			L21: if (mb == 0) {
				/*              No eigenvalue in the current block lies in the desired range */
				/*              E( IEND ) holds the shift for the initial RRR */
				e[iend] = 0.;
				ibegin = iend + 1;
				goto L170;
			} else {
				/*              Decide whether dqds or bisection is more efficient */
				usedqd = (double) mb > in * .5 && !forceb;
				wend = wbegin + mb - 1;
				/*              Calculate gaps for the current block */
				/*              In later stages, when representations for individual */
				/*              eigenvalues are different, we use SIGMA = E( IEND ). */
				sigma = 0.;
				i__2 = wend - 1;
				for (i__ = wbegin; i__ <= i__2; ++i__) {
					/* Computing MAX */
					d__1 = 0., d__2 = w[i__ + 1] - werr[i__ + 1]
							- (w[i__] + werr[i__]);
					wgap[i__] = max(d__1, d__2);
					/* L30: */
				}
				/* Computing MAX */
				d__1 = 0., d__2 = *vu - sigma - (w[wend] + werr[wend]);
				wgap[wend] = max(d__1, d__2);
				/*              Find local index of the first and last desired evalue. */
				indl = indexw[wbegin];
				indu = indexw[wend];
			}
		}
		if (irange == 1 && !forceb || usedqd) {
			/*           Case of DQDS */
			/*           Find approximations to the extremal eigenvalues of the block */
			pdlarrk(&in, &c__1, &gl, &gu, &d__[ibegin], &e2[ibegin], pivmin,
					&rtl, &tmp, &tmp1, &iinfo);
			if (iinfo != 0) {
				*info = -1;
				return 0;
			}
			/* Computing MAX */
			d__2 = gl, d__3 = tmp - tmp1
					- eps * 100. * (d__1 = tmp - tmp1, fabs(d__1));
			isleft = max(d__2, d__3);
			pdlarrk(&in, &in, &gl, &gu, &d__[ibegin], &e2[ibegin], pivmin, &rtl,
					&tmp, &tmp1, &iinfo);
			if (iinfo != 0) {
				*info = -1;
				return 0;
			}
			/* Computing MIN */
			d__2 = gu, d__3 = tmp + tmp1
					+ eps * 100. * (d__1 = tmp + tmp1, fabs(d__1));
			isrght = min(d__2, d__3);
			/*           Improve the estimate of the spectral diameter */
			spdiam = isrght - isleft;
		} else {
			/*           Case of bisection */
			/*           Find approximations to the wanted extremal eigenvalues */
			/* Computing MAX */
			d__2 = gl, d__3 = w[wbegin] - werr[wbegin]
					- eps * 100. * (d__1 = w[wbegin] - werr[wbegin], fabs(d__1));
			isleft = max(d__2, d__3);
			/* Computing MIN */
			d__2 = gu, d__3 = w[wend] + werr[wend]
					+ eps * 100. * (d__1 = w[wend] + werr[wend], fabs(d__1));
			isrght = min(d__2, d__3);
		}
		/*        Decide whether the base representation for the current block */
		/*        L_JBLK D_JBLK L_JBLK^T = T_JBLK - sigma_JBLK I */
		/*        should be on the left or the right end of the current block. */
		/*        The strategy is to shift to the end which is "more populated" */
		/*        Furthermore, decide whether to use DQDS for the computation of */
		/*        the eigenvalue approximations at the end of DLARRE or bisection. */
		/*        dqds is chosen if all eigenvalues are desired or the number of */
		/*        eigenvalues to be computed is large compared to the blocksize. */
		if (irange == 1 && !forceb) {
			/*           If all the eigenvalues have to be computed, we use dqd */
			usedqd = true
			;
			/*           INDL is the local index of the first eigenvalue to compute */
			indl = 1;
			indu = in;
			/*           MB =  number of eigenvalues to compute */
			mb = in;
			wend = wbegin + mb - 1;
			/*           Define 1/4 and 3/4 points of the spectrum */
			s1 = isleft + spdiam * .25;
			s2 = isrght - spdiam * .25;
		} else {
			/*           DLARRD has computed IBLOCK and INDEXW for each eigenvalue */
			/*           approximation. */
			/*           choose sigma */
			if (usedqd) {
				s1 = isleft + spdiam * .25;
				s2 = isrght - spdiam * .25;
			} else {
				tmp = min(isrght, *vu) - max(isleft, *vl);
				s1 = max(isleft, *vl) + tmp * .25;
				s2 = min(isrght, *vu) - tmp * .25;
			}
		}
		/*        Compute the negcount at the 1/4 and 3/4 points */
		if (mb > 1) {
			pdlarrc("T", &in, &s1, &s2, &d__[ibegin], &e[ibegin], pivmin, &cnt,
					&cnt1, &cnt2, &iinfo);
		}
		if (mb == 1) {
			sigma = gl;
			sgndef = 1.;
		} else if (cnt1 - indl >= indu - cnt2) {
			if (irange == 1 && !forceb) {
				sigma = max(isleft, gl);
			} else if (usedqd) {
				/*              use Gerschgorin bound as shift to get pos def matrix */
				/*              for dqds */
				sigma = isleft;
			} else {
				/*              use approximation of the first desired eigenvalue of the */
				/*              block as shift */
				sigma = max(isleft, *vl);
			}
			sgndef = 1.;
		} else {
			if (irange == 1 && !forceb) {
				sigma = min(isrght, gu);
			} else if (usedqd) {
				/*              use Gerschgorin bound as shift to get neg def matrix */
				/*              for dqds */
				sigma = isrght;
			} else {
				/*              use approximation of the first desired eigenvalue of the */
				/*              block as shift */
				sigma = min(isrght, *vu);
			}
			sgndef = -1.;
		}
		/*        An initial SIGMA has been chosen that will be used for computing */
		/*        T - SIGMA I = L D L^T */
		/*        Define the increment TAU of the shift in case the initial shift */
		/*        needs to be refined to obtain a factorization with not too much */
		/*        element growth. */
		if (usedqd) {
			/*           The initial SIGMA was to the outer end of the spectrum */
			/*           the matrix is definite and we need not retreat. */
			tau = spdiam * eps * *n + *pivmin * 2.;
		} else {
			if (mb > 1) {
				clwdth = w[wend] + werr[wend] - w[wbegin] - werr[wbegin];
				avgap = (d__1 = clwdth / (double) (wend - wbegin), fabs(d__1));
				if (sgndef == 1.) {
					/* Computing MAX */
					d__1 = wgap[wbegin];
					tau = max(d__1, avgap) * .5;
					/* Computing MAX */
					d__1 = tau, d__2 = werr[wbegin];
					tau = max(d__1, d__2);
				} else {
					/* Computing MAX */
					d__1 = wgap[wend - 1];
					tau = max(d__1, avgap) * .5;
					/* Computing MAX */
					d__1 = tau, d__2 = werr[wend];
					tau = max(d__1, d__2);
				}
			} else {
				tau = werr[wbegin];
			}
		}

		for (idum = 1; idum <= 6; ++idum) {
			/*           Compute L D L^T factorization of tridiagonal matrix T - sigma I. */
			/*           Store D in WORK(1:IN), L in WORK(IN+1:2*IN), and reciprocals of */
			/*           pivots in WORK(2*IN+1:3*IN) */
			dpivot = d__[ibegin] - sigma;
			work[1] = dpivot;
			dmax__ = fabs(work[1]);
			j = ibegin;
			i__2 = in - 1;
			for (i__ = 1; i__ <= i__2; ++i__) {
				work[(in << 1) + i__] = 1. / work[i__];
				tmp = e[j] * work[(in << 1) + i__];
				work[in + i__] = tmp;
				dpivot = d__[j + 1] - sigma - tmp * e[j];
				work[i__ + 1] = dpivot;
				/* Computing MAX */
				d__1 = dmax__, d__2 = fabs(dpivot);
				dmax__ = max(d__1, d__2);
				++j;
				/* L70: */
			}
			/*           check for element growth */
			if (dmax__ > spdiam * 64.) {
				norep = true
				;
			} else {
				norep = false
				;
			}
			if (usedqd && !norep) {
				/*              Ensure the definiteness of the representation */
				/*              All entries of D (of L D L^T) must have the same sign */
				i__2 = in;
				for (i__ = 1; i__ <= i__2; ++i__) {
					tmp = sgndef * work[i__];
					if (tmp < 0.) {
						norep = true
						;
					}
					/* L71: */
				}
			}
			if (norep) {
				/*              Note that in the case of IRANGE=ALLRNG, we use the Gerschgorin */
				/*              shift which makes the matrix definite. So we should end up */
				/*              here really only in the case of IRANGE = VALRNG or INDRNG. */
				if (idum == 5) {
					if (sgndef == 1.) {
						/*                    The fudged Gerschgorin shift should succeed */
						sigma = gl - spdiam * 2. * eps * *n - *pivmin * 4.;
					} else {
						sigma = gu + spdiam * 2. * eps * *n + *pivmin * 4.;
					}
				} else {
					sigma -= sgndef * tau;
					tau *= 2.;
				}
			} else {
				/*              an initial RRR is found */
				goto L83;
			}
			/* L80: */
		}
		/*        if the program reaches this point, no base representation could be */
		/*        found in MAXTRY iterations. */
		*info = 2;
		return 0;
		L83:
		/*        At this point, we have found an initial base representation */
		/*        T - SIGMA I = L D L^T with not too much element growth. */
		/*        Store the shift. */
		e[iend] = sigma;
		/*        Store D and L. */
		pdcopy(&in, &work[1], &c__1, &d__[ibegin], &c__1);
		i__2 = in - 1;
		pdcopy(&i__2, &work[in + 1], &c__1, &e[ibegin], &c__1);
		if (mb > 1) {

			/*           Perturb each entry of the base representation by a small */
			/*           (but random) relative amount to overcome difficulties with */
			/*           glued matrices. */

			for (i__ = 1; i__ <= 4; ++i__) {
				iseed[i__ - 1] = 1;
				/* L122: */
			}
			i__2 = (in << 1) - 1;
			pdlarnv(&c__2, iseed, &i__2, &work[1]);
			i__2 = in - 1;
			for (i__ = 1; i__ <= i__2; ++i__) {
				d__[ibegin + i__ - 1] *= eps * 8. * work[i__] + 1.;
				e[ibegin + i__ - 1] *= eps * 8. * work[in + i__] + 1.;
				/* L125: */
			}
			d__[iend] *= eps * 4. * work[in] + 1.;

		}

		/*        Don't update the Gerschgorin intervals because keeping track */
		/*        of the updates would be too much work in DLARRV. */
		/*        We update W instead and use it to locate the proper Gerschgorin */
		/*        intervals. */
		/*        Compute the required eigenvalues of L D L' by bisection or dqds */
		if (!usedqd) {
			/*           If DLARRD has been used, shift the eigenvalue approximations */
			/*           according to their representation. This is necessary for */
			/*           a uniform DLARRV since dqds computes eigenvalues of the */
			/*           shifted representation. In DLARRV, W will always hold the */
			/*           UNshifted eigenvalue approximation. */
			i__2 = wend;
			for (j = wbegin; j <= i__2; ++j) {
				w[j] -= sigma;
				werr[j] += (d__1 = w[j], fabs(d__1)) * eps;
				/* L134: */
			}
			/*           call DLARRB to reduce eigenvalue error of the approximations */
			/*           from DLARRD */
			i__2 = iend - 1;
			for (i__ = ibegin; i__ <= i__2; ++i__) {
				/* Computing 2nd power */
				d__1 = e[i__];
				work[i__] = d__[i__] * (d__1 * d__1);
				/* L135: */
			}
			/*           use bisection to find EV from INDL to INDU */
			i__2 = indl - 1;
			pdlarrb(&in, &d__[ibegin], &work[ibegin], &indl, &indu, rtol1,
					rtol2, &i__2, &w[wbegin], &wgap[wbegin], &werr[wbegin],
					&work[(*n << 1) + 1], &iwork[1], pivmin, &spdiam, &in,
					&iinfo);
			if (iinfo != 0) {
				*info = -4;
				return 0;
			}
			/*           DLARRB computes all gaps correctly except for the last one */
			/*           Record distance to VU/GU */
			/* Computing MAX */
			d__1 = 0., d__2 = *vu - sigma - (w[wend] + werr[wend]);
			wgap[wend] = max(d__1, d__2);
			i__2 = indu;
			for (i__ = indl; i__ <= i__2; ++i__) {
				++(*m);
				iblock[*m] = jblk;
				indexw[*m] = i__;
				/* L138: */
			}
		} else {
			/*           Call dqds to get all eigs (and then possibly delete unwanted */
			/*           eigenvalues). */
			/*           Note that dqds finds the eigenvalues of the L D L^T representation */
			/*           of T to high relative accuracy. High relative accuracy */
			/*           might be lost when the shift of the RRR is subtracted to obtain */
			/*           the eigenvalues of T. However, T is not guaranteed to define its */
			/*           eigenvalues to high relative accuracy anyway. */
			/*           Set RTOL to the order of the tolerance used in DLASQ2 */
			/*           This is an ESTIMATED error, the worst case bound is 4*N*EPS */
			/*           which is usually too large and requires unnecessary work to be */
			/*           done by bisection when computing the eigenvectors */
			rtol = log((double) in) * 4. * eps;
			j = ibegin;
			i__2 = in - 1;
			for (i__ = 1; i__ <= i__2; ++i__) {
				work[(i__ << 1) - 1] = (d__1 = d__[j], fabs(d__1));
				work[i__ * 2] = e[j] * e[j] * work[(i__ << 1) - 1];
				++j;
				/* L140: */
			}
			work[(in << 1) - 1] = (d__1 = d__[iend], fabs(d__1));
			work[in * 2] = 0.;
			pdlasq2(&in, &work[1], &iinfo);
			if (iinfo != 0) {
				/*              If IINFO = -5 then an index is part of a tight cluster */
				/*              and should be changed. The index is in IWORK(1) and the */
				/*              gap is in WORK(N+1) */
				*info = -5;
				return 0;
			} else {
				/*              Test that all eigenvalues are positive as expected */
				i__2 = in;
				for (i__ = 1; i__ <= i__2; ++i__) {
					if (work[i__] < 0.) {
						*info = -6;
						return 0;
					}
					/* L149: */
				}
			}
			if (sgndef > 0.) {
				i__2 = indu;
				for (i__ = indl; i__ <= i__2; ++i__) {
					++(*m);
					w[*m] = work[in - i__ + 1];
					iblock[*m] = jblk;
					indexw[*m] = i__;
					/* L150: */
				}
			} else {
				i__2 = indu;
				for (i__ = indl; i__ <= i__2; ++i__) {
					++(*m);
					w[*m] = -work[i__];
					iblock[*m] = jblk;
					indexw[*m] = i__;
					/* L160: */
				}
			}
			i__2 = *m;
			for (i__ = *m - mb + 1; i__ <= i__2; ++i__) {
				/*              the value of RTOL below should be the tolerance in DLASQ2 */
				werr[i__] = rtol * (d__1 = w[i__], fabs(d__1));
				/* L165: */
			}
			i__2 = *m - 1;
			for (i__ = *m - mb + 1; i__ <= i__2; ++i__) {
				/*              compute the right gap between the intervals */
				/* Computing MAX */
				d__1 = 0., d__2 = w[i__ + 1] - werr[i__ + 1]
						- (w[i__] + werr[i__]);
				wgap[i__] = max(d__1, d__2);
				/* L166: */
			}
			/* Computing MAX */
			d__1 = 0., d__2 = *vu - sigma - (w[*m] + werr[*m]);
			wgap[*m] = max(d__1, d__2);
		}
		/*        proceed with next block */
		ibegin = iend + 1;
		wbegin = wend + 1;
		L170: ;
	}

	return 0;

	/*     end of DLARRE */

} /* dlarre_ */
